Nest Thermostat Gen 3 - Dual Zone Install Danfoss HPA2 valves for upstairs and downstairs

[thaisalvesbr]

Help with dual zone wiring - Nest thermostat UK

Hi, I am following a diagram and installing the heatlink to the wiring centre. Seems all should be correct but it puzzles me that the brown wire of the danfoss HPA valves are going into the black wire of the thermostat but on my thermostats this is going into COM not NO.

At moment the plan is:

1. Blue neutral from Valve to Neutral in heatlink
2. Grey Live from Valve to Live in heatlink - remove the stats wires to use on T1
3. Orange from Valves leave as is to boiler only
4. Brown from Valves each to a corresponding terminal 3 (NO) in heatlink - remove the stat wires to use on T2.
5. Also bridging L to 2 in heatlink

The wires coming from the very bottom in the wiring centre picture are from the valves, there are also 2 loose neutrals from the stats as they were not needed. On the left are the boiler wires, the stats wires are the ones coming from the wall on bottom right.

Maybe I am overthinking but I don’t understand why the black wire from the stat is going into COM? Voltage measured on NO is 230v whilst 12V on COM on the stats…

The connectors have been also installed to plate upside down and do not match the labels but I figured based on the valves wiring.

I hope this makes sense to someone who is able to help.

 

[ianmcd]

on my thermostats

Help with dual zone wiring - Nest thermostat UK

A bit confusing, is it one heating zone and one HW zone? or seperate upstairs and downstairs heating zones and a HW zone ?

 

[thaisalvesbr]

Apologies for the confusion.

The valves are in the same airing cupboard and one controls the upstairs and the other downstairs heating.

All the wiring is in that centre.

 

[thaisalvesbr]

To add I have two thermostats, one upstairs and one downstairs.

 

[CBW]

To add I have two thermostats, one upstairs and one downstairs.

Odd, I can only see x2 orange wires, so unless your hot water is wired in another wiring center?

 

[thaisalvesbr]

Nothing else in the house… it’s an ideal combi boiler… I have been following the same as this thread as all seems the same apart from my thermostats are battery powered.

Thread 'Nest Thermostat Gen 3 - Dual Zone Install'
https://www.diynot.com/diy/threads/nest-thermostat-gen-3-dual-zone-install.601653/

 

[CBW]

Ah, much more sense. You're probably measuring the switch live which will only be 230v once switched, so why you're only getting 12v. If you're keeping x2 zones you'll need another Nest

 

[thaisalvesbr]

I have two to intall just making sure I am doing the correct thing with the wires but confused to why my com stats wires seems to be going into the brown wires on the valves as I thought these needed to be for the NO?

 

[CBW]

The way it'll work is you request heat from thermostat which will send switch live (NO) to zone valve which will motor open and send another switch live from orange to boiler via zone valve microswitch.

 

[thaisalvesbr]

That makes sense… shall I worry at all that the current stat has the brown wire that are going on the grey of the valves and the black that is currently on the COM on the brown of the valves on the left? I thought this needed to be the e other way round…?

 

[CBW]

No, should be ok.

 

[thaisalvesbr]

So the original set up I was looking at should work?

 

[ianmcd]

Apologies for the confusion.

The valves are in the same airing cupboard and one controls the upstairs and the other downstairs heating.

All the wiring is in that centre.

Then you will need two nest thermostats and two nest receivers, dual channel means one heating zone and one HW zone it doesnt mean 2 heating zones

 

[thaisalvesbr]

Thank you for clarifying